1. Field of the Invention
This invention relates to an air bag module for use on the driver side of automotive and other vehicles wherein an inflatable air bag or cushion is inflated in the event of a collision to protect the driver from injury that could result from being forcibly thrown against the steering wheel, dashboard, etc. The air bag module uses an off-center positioned tubular inflator.
2. Description of the Related Art
Inflator assemblies that currently are in use in driver side air bag modules typically are toroidal types having flat, disk-like shapes. With the dimensions of the inflator assembly characteristically being about two inches (2") thick and four inches (4") in diameter, much of the inflatable cushion stored in the air bag module is folded in front of the inflator assembly as opposed to the sides thereof. While an inflator assembly having a tubular shape would allow much of the cushion to be folded on the sides thereof in an air bag module, a tubular inflator assembly will not fit in driver side air bag modules as they are currently designed.
Inflator assemblies of the toroidal type produce a cushion inflating gas source from a combustible gas generating material which, upon ignition, generates a quantity of gas sufficient to inflate the cushion. One form of tubular inflator assembly similarly is operative to generate gas for inflating cushions from a combustible gas generating material. In another form of tubular inflator assembly, however, the cushion inflating gas results from a combination of stored compressed gas and a gas generating material. The latter form of tubular inflator assembly is commonly referred to as an augmented gas or hybrid inflator. Hybrid inflators affect the performance of air bag modules in several ways including variation in the amount of stored gas, the transmission of heat to the stored gas, and the rate at which the inflating gas is dispensed into the inflatable cushion.
In U.S. Pat. No. 5,290,059 that was issued on Mar. 1, 1994 to Bradley W. Smith, Gary V. Adams and Kirk Rasmussen and assigned to the assignee of the present invention, there is disclosed an air bag module for use on the driver side of automotive and other vehicles which utilizes a center mounted tubular inflator. A different housing, retaining ring, cushion and inflator bracket are used than are employed in air bag modules of current production. The appearance and function of the module are not changed but only the internal components. The center mounted tubular inflator of the Smith et al. patent is located in a slotted section of the module housing with the diffuser thereof protruding upwardly from the center through a hole in a raised portion of the module housing slotted section, which hole is sized closely to the size of the diffuser. The diffuser extends directly into the module at a 90.degree. angle to the plane surface of the housing. The retaining ring has raised portions in the center thereof to match the raised portion of the module housing, has holes in the raised portions, and has tabs which extend through holes in the cushion and the module housing. The module housing has tabs on the raised portion thereof which extend through holes in the cushion and retaining ring. The cushion uses a rectangular mounting so that the cushion matches the radius of the module housing in the raised portion which goes over the tubular inflator. The retaining bracket extends around the back side of the inflator to hold it in place and includes cover retaining brackets. Studs which hold the module together extend from the retaining ring through holes in the cushion, module housing and retaining bracket.
Driver side air bag modules, which are currently produced, use a toroidal inflator in them. There is a need and a demand to provide a driver side air bag module in which a tubular inflator assembly may be used to facilitate folding of much of the cushion on the sides of the inflator and to affect the performance of the air bag module, and, additionally, which allows the envelope of the module to be smaller than that obtained using the center mounted tubular inflator arrangement of the aforementioned Smith et al. patent. The present invention was devised to fill the technological gap that has existed in the art in this respect.